Combined gun equilibrator and elevation cylinder



L. BRUEHL July 26, 1960 -2,946,262 COMBINED GUN EQUILIBRATOR AND ELEVATION CYLINDER Filed Sept. 12, 1952 5 Sheets-Sheet 1 INVEN-oR LAWRENCE BRUEHL mm JM ATTORNEY LLL-(lill July 26, 1960 L.. BRUEHL COMBINED GUN EQUILIBRATOR AND ELEvATroN CYLINDER Filed sept. 12, 1952 5 Sheets-Sheet 2 L M. L

lNvENToR LAWRENCE yBRUEHL BY 64Mb/ LM ATTORNEY July 26, 1960 L. BRUEHL 2,946,262

COMBINED GUN EQUILIBRATOR AND ELEVATION CYLINDER Filed Sept. 12, 1952 5 Sheets-Sheet 3 l i o if: FIGJC TLT 621 l K 57 n" L6l v /37 Jlf2 /fa /00/ /37 124 lNvENToR LAWRENCE BRUEHL July 26, 1960 l.. BRUEHL 2,946,262

COMBINED GUN EQUILIBRATOR AND ELEVATION CYLINDER Filed Sept. l2. 1952 5 Sheets-Sheet 4 F162 l ff 6/ 7 v6'@ 54 E?" 6 Y 5 E? 9! I {""J94 Frmd lNvx-:N'roR LAWRENCE BRUEHL 40 BYJMM/ M ATTORNEY L. BRUEHL July 26, 1960 COMBINED GUN EQUILIBRATR AND ELEVATION CYLINDER Filed Sept. 12, 1952 5 Sheets-Sheet 5 MGI INVENTOR LAWRENCE BRUEHL BMM ATTORN EY COMBINED GUN EQUL'IBRATOR AND ELEVATION CYLINDER Lawrence Bruehl, Vestal, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Sept. 12, 1952, Ser. No. 309,344

13 Claims. (Cl. 89-37) The present invention relates to improvements in equilibrating systems, elevating systems and shock absorbing systems for guns utilized in tanks. The present invention constitutes `an improvement over the equilibator shown and described in my copending application Serial No. 309,345, tiled September 12, 1952.

In the equilibrating system of the aforesaid copending application, there is provided an equilibration cylinder and a separate hydraulic elevating cylinder, which cylinder is also utilized to detect unbalanced forces on the gun.

According to the present invention and in order to provide increased compactness of parts, the elevation cylinder and equilibration cylinder are provided in a single unit. This single unit construction provides increased compactness in parts and provides additional space in the tank turret, and also permits the lowering of the overall height of the tank turret. Combined with the single unit equilibrator and elevator structure, there is provided means for absorbing shocks.

According to the present system, counterbalancing equilibrator pressure is provided, together with means for regulating the equilibration pressure at times when there is an unbalanced force on the gun. Provision is made for detecting the unbalanced force and controlling the regulation of the equilibrating pressure accordingly.

The system of this invention employs a common piston rod which functions in the equilibrator as Well as in the elevation system. There is a concentric arrangement of pistons with an inner one for the equilibrator and an outer one for the elevator. Combined with these in the same unit is a pneumatic shock absorber. The shock absorber involves a group of interacting pistons and a gas chamber, the pistons being concentrically disposed with respect to the equilibrator and elevator pistons.

Included in the system is an improved overload bypass for the elevator hydraulic system to prevent building up of excessive stresses when abnormal forces are imposed upon the system.

This invention includes an improved unbalanced force detecting valve which may be located in a separate unit and which acts to control the regulation of the equilibration force being applied to the gun. Y

By means of this invention, the differential piston unit which was a maior element of the older type equilibrator, is entirely dispensed with, which greatly simplit'ies the system and reduces the amount of material necessary to construct the system. This invention provides a pneumatic system for eiecting equilibration in lieu fof a fully hydraulic system as formerly employed and provides means for regulating the pneumatic pressure to vary the amount ot the equilibration force. Specifically, the improved unbalanced force detecting means, i.e. valves, controls the regulation of the pneumatic force applied by the equilibrator.

Another object of this invention is to provide an elevation cylinder with a shock absorber to elastically cushion the effect of shocks which would otherwise build up excess pressure in the elevating cylinder, with associatedmea'ns to `allow .the escape of liquid from theeleva- ,tion cylinder and to return the liquid to the cylinder'a'ft'er the elect ofthe shock has been dissipated;

Other and more detailed objects of the Apresent invention will appear in the following detailed specification and will be pointed out in the appended claims, when lconsidered in conjunction with the accompanying drawings, in which:

Figs. la-ld, inclusive,r show a schematic layout ofj the improved equilibrator and elevation cylinder ot thisrinvention with the major elements shown in cross-section;

Fig. 2 shows a diagram.y of therelative positions ofthe four sheets of drawings which contain Figs. lez-1d vin order to properly join the elements of the system, which are shown on more thanA one. sheet ofdrawin'gs; Vand Y Fig. .3 shows a fragmentary side view partly in'crosssection of .an equilibrator-and-elevation. Vcylinder unit mounted on a gun and turret of a tank. p As previously explained in my copending application mentioned' above, an equilibrator is a device used inl connection with a gun when the'gun is mounted with `its center of gravity offset fromthe trunnion axis. These 'conditions are found almost universally inV tanks Afrom' force'of necessity in the'aspects of. the design of a tank. The function vof the equilibrator then is to apply a counter-balancing force to the gun so that it is in balance about its trunnion axis and may easily be elevated or depressed without undue strain on the elevating mechanism. Because theh'orizontal distance of the center of gravity' of the gun from its trunnion axis varies with the elevational position of the gun, the equilibration force necessaryV to balance the gun must also be varied. This equilibration force may be made to approach a correspondence vwith Vthe unbalanced force of the gun byproper geometric arrangement of the points where the equilibrator is fatl tached to the gun and to theturret; however, some discrepancies will be present. Ina tank the elevational posiytionsof thegun where discrepancies occur, do not remain constant, e.g. in traveling over rough terrain, the :hull and turret will `change position relative to the horizon. Therefore, it is on a tank that the system of this invention is particularly beneficial in that this invention permits the continuous regulation of the equilibration force to counter-balance the unbalanced forces of the 'gun'at' all times "and in all elevational positions.,

A specic embodiment of this invention is shown in 'the drawings Where Figs. laand lb illustrate a combina.

Vtion equilibration andY elevation cylinder and piston device A9vvhich is shown mounted on agun and turret in Fig. 3. This unit 9 is operated in conjunction witha hydraulic `system illustrated by the Figs. `la through ld; which serve VtoV accomplish the purposes set forth above. The con bination unit 9 is composed of a pistonV 10 whichhas abracket 12 threaded to the right end of. its piston rod 11 asfviewed in Fig. 1b. The bracket l2 contains a spher-V ical needle vbearing A13` p (needles not shown) `located therein forattaching the unit to either a gun 14 (Fig. 3) orto a turret l5. Piston 10 travels in a cylinder 16Y which is located fat the right end of the unit as viewed in Figs. la and lb; Cylinder 16 is securely attached to the body section 17 of therunit 9. The body section 17 is com,- posed of a number of sections which are alli-securely fastened together. At the left end of the body section 17, there is a bracket member 18 which is fastened to the body section-17 ina similar Vmanner as is the bracket 12 to pistonrod 1 1, and which likewise is for attaching the unit to either the gun or the turret, if the unit is being used in a tank. It -will be observed that piston rod 11 is hollow v` and carries a floating piston 19 inside, whichsepa- -rat'e's the hollow centerof piston rod 1 1 into two sectionsV 20 and 21. When the unit is in use, hollow section 20 'Will be completely lled with hydraulic fluid 'while vhollowI section 21 (to the left of the floating piston 19 as viewed n Figs. la and lb) will be iilled with a gas under pressure. Gas under pressure Will also fill a hollow chamber 22 of the unit. Chamber 22 is directly connected to section 21 of the hollow piston through a large opening 23.

By a general reference to the unit 9, the operation of the unit to act as an elevation cylinder and also as an equilibration cylinder will now be pointed out. It will be noted that the parts are shown completely telescoped, i.e. elevation cylinder 16 and piston 10 are at one extreme position which produces the shortest distance between the centers of brackets 12 and 18. When used in a tank (as illustrated in Fig. 3 of the drawings), the gun would be at its lowest elevational position (see also the dotted line position 24 of parts in Fig. 3). In order to elevate the gun, hydraulic lluid will be introduced into an annular chamber 28 to the left of piston 10 (see Fig. 1b). This will tend to cause the piston 10 to move to the right, as viewed in the drawings, extending bracket 12 and elevating the gun. Hydraulic uid which is already in chamber 29 on the other side of piston 10 will be expelled through passage 30 and then on via a hydraulic circuit to be traced later. Equilibration forces are applied to the gun by means of gas under pressure in chamber 22. Such gas will be introduced via passages 31 and 33 (Fig. la) in bracket 18. These gas inlet passages 31 and 33 terminate on the outside of bracket 18 by means of an inlet port (not shown) which contains a check valve (not shown) therein to facilitate the charging of chamber 22. Passages 31 and 34 lead to a port 35 to which is attached a gage 32 for determining the pressure existing in chamber 22. As previously mentioned, there is hydraulic fluid in section 2t) of piston rod 11, which uid is, of course, substantially incompressible. Therefore, assuming that there is no change in the quantity of fluid in section 20, the gas under pressure in chamber 22 and section 21 will exert a certain force on piston rod 11. Whenever this force is equal to the unbalanced force of the gun about its trunnion axis (Fig. 3), the equilibrator is working perfectly and needs no regulation. It will be noted, however, that as the gun 14 changes its elevational pistons, the piston rod 11 will be more or less extended, e.g. note dashed line positions 24 and 26 of unit 9 (Fig. 3). Slch changes in position of piston rod 11 will correspondingly change the position of loating piston 19 with respect to the body section 17, because the gas pressure in section 21 of the hollow piston rod 1l will hold floating piston 19 in pressure contact with the hydraulic lluid in right-hand section 20 of the piston rod 11. These changes in the position of floating piston 19 with respect to body 17 cause corresponding changes in the volume of the gas chamber made up of hollow chamber 22 and section 21 of the piston rod 11. The change in volume of this gas chamber will change the pressure of the gas within the chamber and consequently will change the equilibration force applied to the gun. Whenever this equilibration force is not equal and opposite to the unbalanced forces of the gun, there will be a tendency for the piston rod 11 to be further extended or for it to be pushed back into the body section 17 depending upon which way the inequality of forces exists. In either case, by sensing means to be described below, such tendency to move piston rod 11 will tend to move piston which is an integral part of piston rod 11 and so will set up unequal pressures on the hydraulic uid on either side of piston 10. These unequal pressures are used to cause a change in the quantity of hydraulic fluid in section of the piston rod 11 and this, in turn, will move floating piston 19 to the left or right with respect to piston rod 11. This action will compress or expand the gas in chamber 22 and section 21 and correspondingly vary or regulate the pressure of this gas and so correct the equilibration force to make it equal and opposite to the unbalanced force on the gun.

In order to describe the manner in which the regulation of equilibration force as mentioned above is accomplished, the details of the operations of the system will now be described. It will be noted that there is a complete hydraulic system which includes a sump or reservoir 36 (Fig. 1d), a manual pump 37 (Fig. lc), which has a handle 38, a fragment of which is shown, and a hydro-pneumatic accumulator 39 which provides compressed gas for applying a working pressure to 4the hydraulic system. Since the system uses very little hydraulic fluid, accumulator 39 could be charged from some other hydraulic system if one is available. Such charging means would be connected to hydraulic pipe 123 (Fig. lc). Only in very rare cases does it become necessary to operate hand pump 37.

Assuming that system pressure has been obtained by operation of the manual pump 37 to charge accumulator 39, the ilow `of hydraulic fluid for operating the elevation cylinder and piston will rst be traced. Beginning at a hand circulating pump 40. (Fig. ld), when the liandle of circulating pump 40 is rotated in `a given direction, hydraulic lluid will be circulated out through pipe 44 to port 45, and thence through Va passage 46 to a chamber 47. This chamber and this passage are part of a hydraulic no-back device 4S which operates to allow iluid to be circulated in either direction by the hand circulating pump 48, but which cuts o any return flow of fluid back from the system which might cause the hand pump 40 to motor, i.e. apply rotational force back on the handle of pump 40. Such no-back action is accomplished because of the action both by piston 51, which has two pins 52 and 53 integrally attached thereto, and by means of a pair of spring-loaded check valves 54 and 55. When fluid is circulated from the hand pump 46 into chamber 47, pressure in chamber 47 is increased and piston 51 is moved to the right, as viewed in Fig. ld. This action causes pin 53 to raise a ball 56 from its seat against the pressure of a spring 57, and so to allow the return fluid to be circulated. At the same time, the pressure increase in the chamber 47 raises ball 59 from its seat against the Apressure of a spring 58, which allows circulation of the uid to continue through a passage 68 and out through hydraulic pipe 6l.

The circulation will continue through pipe 62, pipe 63 (Figs. lc, 1b and la), pipe 64 to port 65, thence through passage 66, annular chamber 67, upper passage 68, port 69 and hydraulic pipe 70, and form hydraulic pipe 70 to port 71, passage 72 to annular chamber 28. This will then tend to move piston 10 to the right and hydraulic uicl will be returned from chamber 29 via passage 30, a port '76, hydraulic pipe 77, passage 78, annular chamber 79, passage 30, hydraulic'pipe 81, passage 82, annular chamber 83, passage 84, hydraulic pipe S5 (Figs. la, lb and lc), hydraulic pipe 86, hydraulic pipe 87 to port 88 in rio-back device 48, and finally through passage 91 past now open Valve 55 to chamber 92 and passage 93, hydraulic pipe 94 and back to the hand circulating pump 40 affording a complete circulation of fluid.

Whenever unbalanced forces on the gun exist, .which are not counter-balanced by the equilibration section of unit 9, the piston 10 will tend to move in one `direction or the other in its cylinder 16. Such a tendency to move by piston 10 will set up adilerence of hydraulic pressure on the two sides of this piston. This difference will be detected by a sensing device 98 (Fig. lc), the action of which will now be described. Assuming the pressure in hydraulic pipe 86 is greater than that in pipe 63, each of which leads back to an opposite side of piston 10 by circuits just traced above, hydraulic pressure'in pipe 86 will be transmitted via pipe 100 and passage 101 to annular chamber 102 and cause piston 99 to be moved to the left as viewed in Fig: lc; Movement of-piston 99 to the left Will cause poppet valve'103 tobe opened by means of an integral sleeve 104 of piston 99.; Opening of this poppet valve 103 connects an endchamber amazes E '109 to a hydraulic circuit that leads to hollow section 20 of piston rod 11 in combination unit 9. This hydraulic circuit is readily traceable and is as follows: from Achamber 109, through a passage 105, hydraulic pipe 106 (Figs. lc and 1b), hydraulic pipe 107, and passage 10S in bracket 12 to hollow section 20. Opening of poppet valve 103 in sensing device 98 therefore connects hollow section 20 of piston rod 11 to system return or the sump 36 (Fig. 1d) by the following hydraulic circuit: beginning at chamber 109, which is directly connected to hollow section 20 as just traced above, the flow cf uid may be past now open poppet valve 103 to annular chamber v110, passage 111, hydraulic pipe 112, hydraulic pipe 113, and hydraulic pipe 114 to the sump 36. This'then allows hydraulic fluid to drain out from hollow section 20 of piston rod 11 (Fig. lb) and therefore allows floating piston 19 to be moved to the right which expands Athe gas in chamber 22 and hollow section 21 reducing the pressure. The effect of this change is to regulate the equilibration force being applied to the gun. When the unbalance is in the opposite direction and Aan increase of equilibration force is called for, the hydraulic pressure on the left side of piston will be greater than on the right side and, therefore, this increase of pressure will be transmitted via the hydraulic circuit previously traced to hydraulic pipe 63 and from there to hydraulic pipe 118, passage 119, in the sensing device 9S, to annular chamber 120 on the left side of piston 99. This time the acti-on will be the reverse of that just described and piston 99 will be moved to the right whereby its sleeve r121 will cause poppet valve 122 to be opened and this time hydraulic uid under system pressure will be admitted to hollow section 20 of piston rod 11 by means of the following hydraulic circuit. Beginning at accumulator 39, fluid will flow via hydraulic pipe 123, hydraulic pipe 124, passage 125, annular chamber 126, past the now open poppet valve 122 into end chamber 127. From end chamber 127, nid may ow through central passages 12.8, 129 and 130 to end chamber 109 and thence via the hydraulic circuit already traced above to section 20 .of hollow piston rod 11. This introduction of hydraulic fluid under pressure from the system will increase the quantity of hydraulic lluid in section 20 of the piston rod and will, therefore, move floating piston 19 tothe left The poppet valves 122 and 103 of sensing device 98l are held in a seated position as illustrated, by means of springs 135. The amount of spring pressure applied by these springs may be regulated by means of screws v136. There are seals used wherever necessary to isolate hydraulic chambers and the like, throughout the sensing device. The same is true with the other Velements of the system, e.g. the equilibration-elevation unit 9 and the no-back device 48. All pistons have rings or some vappropriate type of seals to keep any leakage past the pistons to a minimum.

There are three adjustable restrictions in the sensing device 98 which are formed in each case by a' needle valve. Each needle valve is composed of a threaded core member 137 which has a slotted top for'adjustmentby means of a screw-driver and a valve seat 138 which determines the amount of restriction imparted to the llow of hydraulic tlnid by the needle valve. The purpose of these needle valves v137 is to restrict the flow of hydraulic fluid in order to throttle the reaction of the sensing means 98 so that it will not be oversensitive. That is, the purpose of the restrictions is to keep the sensing means from reacting to transient shock conditions, such as may be encountered in ordinary travel of a tank over of hydraulic pressure 'created by forces on the elevation cylinder 16 and piston 10, sets up 'a tendency for hydraulic uid to circulate from one side of central piston 99, of the sensing means, to the other. Therefore, whichever direction the iiuid is circulating, a restriction in one side is effective to restrict movement ofsensing piston 99 and consequently to restrict the sensitivity to transient conditions. On the other hand, restrictive ne'edle valves 137 are necessary in each of the separate hydraulic circuits leading to the system pressure line vand to the system return line because these two hydraulic circuits are connected in the alternative to the hydraulic circuit which leads to the equilibration hydraulic system, and when one is connected the other is not, so that ya separate restriction is'needed for each. 1 Y

Means to absorb shocks of an `appreciable duration as ielt by the gun about its trunnion axis, are'provided within unit 9. Such means mainly consists of an auxiliary gas chamber 141 (Fig. 1a). This gas chamber is bounded by a pair of annular pistons 142 and 143. `(ias cham-ber 141 will 4be charged to a predetermined pressure through a vent 14twhich is shown closedby a screw 145 having a passage therethrough which contains Va check valve (not shown) therein, to hold the gas under pressure as charged into chamber'141. There is. a pres- `associated elements is to absorb two types lof shocks First, there is kthe v which occur during tiring of the gun. shock which occurs as a result of the axis of the gun barrel not intersecting the axis of the trunnion bearings.y lf

fthe axis of the gun Abarrel is above or below the axis of the trunnion bearings (above is most common), thejgun recoil in rtiring acts to create a torquejabout the'trunnion axis which tends torwhip the v-gun barrel up or'down respectively. This shock load will bey absorbejdpby the Vshock absorber section presently to tbe described. `Sec l ond, there is the shock which occurs when the gun barrel 139 and breach 140 (see Fig. 3) move backwardsin 'their-mount 14 (also lFig. 3), which mount has been referred to as they gundd. VSuch recoil ymoves'the center of gravity of the ywhole gun backward rapidly and upsets the state of balance of forces on the. gun which was existing due to the equilibrators action, and'this sudden rough terrain. There is only one needle valve 137 forY upset creates a shock load onthe unit 9 which is yabsorbed by the saine shock absorber section of the equiliof piston 10. The pressure thus set up will be absorbed by the gas in chamber '141 which will be compressed byV movement of either annular piston 142 -or143. The action of both of these pistons is identical, the only difference being that each one is located in a separate hydraulic annular chamber 79. At this point, this increase in AVpressure will move a sleeve-shaped piston 159,1,0 theleft. This piston 159 will in turn -move annular piston '142,

7 against which the left end of piston 150 rests, to the leftalso. Such movement of piston 142 will compress the gas in chamber 141 which absorbs the shock or overload by allowing iluid to flow into annular chamber 79. Since uid is allowed to ow into annular chamber 79 from chamber 29, piston will be allowed to move te the right. Therefore, there will be a reduced pressure created on the other side of piston 10 and hydraulic iluid will tend to ow into chamber Z8 on the left or low pressure side of piston 10. The source of such uid will be the annular chamber 67 which is on the opposite side of the fluid-tight piston 150 from the annular chamber 79. In other words, when the shock conditions cause high pressure in the hydraulic iluid lines adjacent to piston 10, sleeve-shaped piston 150, or corresponding sleeveshaped piston 151, will be moved to the left or to the right respectively, which will absorb these high pressures. Such movement, however, is only possible against the force of gas under compression in chamber 141 and, therefore, when the shock load conditions have ceased, the gas in chamber 141 will move annular piston 142 or 143 back to the position shown which, in turn, will move sleeve piston 150 or 151 back to its extreme position shown, and this movement in its turn will cause a return ow of hydraulic iluid which will reposition piston 10 to the original Iposition within its cylinder 16 where it was before any shock load was felt.

It will be noted that the shock absorbing means just described allows an angular displacement of the gun about its trunnions to take place, but this displacement is absorbed by an elastic medium, namely, gas in chamber 141, so that when the shock load is gone the gun will be returned to its original position by the action of the elastic medium which returns the piston (either 142 or 143) which compressed the gas to its original position, i.e. that shown in the drawings.

To be entirely clear, assume that piston 10 is located in a more or less central position in its cylinder 16 and that a shock load is felt by the system tending to move piston 10 to the left. As soon as the force tending to move piston 10 reaches a predetermined level (which will be determined by the pressure of the gas in chamber 141) the piston will move. This will force hydraulic fluid out of chamber 28, via passage 72, port 71, hydraulic pipe 70, port 69, passage 68, annular chamber 67, passage 66, port 65, pipe 64, pipe 149, passage 148 to annular charnber 147. Here the uid owing into chamber 147 will force piston 151 to move to the right, as shown in the drawings, and consequently to push piston 143 to the right, compressing the gas in chamber 141. At the same time, fluid in annular chamber 83 on the other side of piston 151 will be forced out via passage 82, pipe 81, passage 80, annular chamber 79, passage 78, pipe 77, passage 30 to chamber 29, which is on the other side of elevation piston 10. This then supplies thevcirculation of uid that is necessary to move piston 10, and the compressed gas in chamber 141 acts as an elastic medium to return the fluid in the reverse circulation to return piston 10 to its original position, after the shock load is gone.

There is a means for taking care of extreme overload conditions of such a magnitude that the various elements of the system might be stressed to the breaking point. This means is composed of a pair of spring-loaded check valves 152 and 153 (Fig. lc). These check valves are of the ordinary spring-loaded ball type and are constructed with heavy springs 154 and 155 respectively, such that in all normal operating conditions, both valves will remain closed. If extreme loads should be applied to the system, shock absorber chamber 141 would be compressed to its extreme condition rst, and then further pressure (which might cause mechanical failure) would be relieved by one of the check valves 152. or 153 depending upon which'direction the load is applied to the system. The opening of this valve would allow a by-pass action of hydraulic uid from one side of elevation piston 10 to the '8 other as it is moved to relieve the load, and in this case a permanent deilection of the gun will be caused.

The system illustrated is entirely 'manual in order to simplify the disclosure. However, power elevation or depression of the gun is usually included in an equilibration and elevation system such as that of this invention. This power elevation control may be had when the main hydraulic system of the tank, in which the system is located, is connected into the system. To effect such connection, the pressure side of the main hydraulic system would be connected to the accumulator 39 while the return side would be connected to the sump 36. Therefore, the accumulator 39 would be kept charged up without operating manual pump 37-in the operation of the system as described, it has been assumed that manual pressure pump 37 is being operated whenever necessary to maintain system pressure at a predetermined level-then, in order to control elevation of the gun under power instead of by hand pump 40, there would be a valve, or set of valves (not shown), which would operate to connect the pressure and return sides of the system to the two sides of elevation piston 10 reversibly, depending upon which way the elevation piston was to be moved. Of course, such a valve control would have a neutral position for stopping the elevation piston in any given position. The main hydraulic system would include a power driven circulation pump (not shown) to be connected to the main hydraulic system (which includes accumulator 39 and sump 36) so that the gun might be repositioned in elevation by a power control rather than only by means of a manual pump such as hand pump 40. This system could be made fully automatic by use of gyro responsive valvular means (not shown) which would be connected to hydraulic pipes 61 and 87 over a no-back device (not shown) in a similar manner as the hand elevation pump 40 in Fig, 1a.

There is a drain valve 156 (Fig. 1b) which is connected between hollow section 20 of piston rod 11 and system return or the sump 36. This valve is ordinarily kept shut, its purpose being merely that of draining hydraulic iluid from section 20 of the equilibrator unit 9 when the unit is not in operation.

In the construction of the system, some of the units may be conveniently combined into a single housing, e.g. the sensing device 98, the overload by-pass valves 152 and 153 and the no-back device 48. This is merely a matter of design and does not change the principles of the invention disclosed. A single housing such as just mentioned, might conveniently be mounted in at least three diierent locations, e.g. by being attached to the cylinder unit 9, to the gun 14, or to the turret 15. The same holds true for hand circulating pump 40. It would be most convenient for the hand pump 40 to be attached to the same thing that the gunners seat (not shown) is attached to, i.e. the gun 14 or the turret 15, so that there would be no relative motion between the hand pump and the gunners seat.

There are three chambers 159, and 161 in the unit 9, which are open to the atmosphere and allow free circulation of air by means of vent passages 163, 16'4 and-165 respectively. The purpose of venting these chambers is to avoid any back pressure from trapped air. These chambers might also be vented to the sump.

Th diagram of Fig. 2 is self-explanatory and show the relative positions of the four sheets of drawings when the connected parts are adjoining one another.

Fig. 3 shows the gun mount 14 mounted on the turret 15 by its trunnions 168, the axis of which is indicated by reference number 25. This figure also shows unit 9 attached to the gun mount 14 and to turret 15 by means of brackets 169 and 170 respectively which are suitably fastened to the gun mount and turret as by bolts shown.

Flexible couplings 171 (Fig. lb) will be included in the hydraulic pipes at appropriate places in the system, which will be determined by the location of the combined unit 9. For` example, with theunit mountedas shown in Fig. 3, `iiexible, couplingswould be necessary at or near the two brackets `12 and vLl8`of the unit 9, as well as near the gun trunnions 25. Such location of necessary flexible couplings is a matter of designing the system for use in a particular vehicle, e.g. a tank as here illustrated.

A major achievement of this invention is that the gun can be turned smoothly and evenly through its arc with very little unbalance` This is the result of careful mathematical calculations in respect to the linkage mathematics correlated to the gas pressure mathematics (referring to Fig. 3). Both are a function of the three suspension points, viz. the trunnion axis 25, the pivot axis of attachment to the gun by brackets 12 and 169, and the pivot axis of attachment to the ceiling of the turret by brackets 18 and 170. The force exerted by the gun along the Jline joining the two pivot axes as a rfunction ofk gun angle represents a certain curve. kThe counter-balancing gas pressure exerted along the same line as a function of gun angle represents another curve. VAn outstanding feature of this invention consists in that both curves are calculated so as to have a minimum deviation from each other. In fact in each half of the arc of gun movement there is a point of perfectvbalance with the plus and minus unbalances cancelling out. In this balance calculation the deviation of the tank off horizontal position was also considered.

Actual tests have shown thatshocks of considerable intensity (up to three times gravity) .can be absorbed by the equilibrator cylinder unit of `this invention and lcan be damped in 11/2 to 2 oscillations w'ith'properly calculated dimensions and friction conditions.

Operation In order to summarize the main features of the invention, the operation of the device will. be reviewed.. Referring to Figs. 3, and la, lb and 1c, when the gun 14 is static about its trunnion axis 25 relative to the turret 15, the force created by the equilibrator (as determined by the gas pressure in chambers 21 and 22 of the entire unit 9) equals the opposite force created by the torque of the center of mass of the gun which is offset from -the -trunnion axis 2S. The gun may be tilted within a predetermined angular range as limited by the size and location of the parts. Such tilting is accomplished by the elevation cylinder and piston arrangement that includes cylinder 16 (Fig. lb) and piston 10. Hydraulic iluid is introduced, over the hydraulic pipes illustrated, to one side or the other of the piston 10 within the chamber 29, while the other side of the piston `10 is connected to the return side of the hydraulic system. In this way the piston 10 will be positioned longitudinally within cylinder 16 and so cause a changein the effective length of the entire unit 9, yand thereby cause a change in the angular position of the gun 14. lf, however, at any time the gun 14 becomes unbalanced about its trunnion axis 25, unequal -pressures will be vcreated on the two sides of piston Citi.. The higher pressure on one side of piston 1li will be transmitted over the hydraulic circuit illustrated to one side or 'the other of the central piston 99 (Fig. lc) located inthe sensing device 98. At the same time, the other side of this .central piston 99 is connected via another hydraulic circuit illustrated to the low pressure side of piston 10. For this reason, the central piston 99 of the sensing device 98 will be displaced either to the left or to the right as viewed in Fig. 1c and will thereby open one or the other of the poppet valves 103 or 122. The opening 0f one of these poppet valves 103 or 122 will cause hydraulie iiuid to be drawn from, or added to, the section 20 (Fig. 1b) of the hollow piston rod Vlll. In this way the lloating piston 19 will be repositioned to the left or to the right within the hollow piston rod 11 and consequently increase or decrease the pressure of the gas contained in chambers 21 'and 22 (Fig. la) of the agria-epee Y unit'9. `Such lchange Aof pressure ofthe 'gas willchange the equilibration force being Vapplied by the'equilibra'tor section of the unit 9, in such a way as to tend to reduce the unbalanced forces'on the gun to zero. This action is the same basic situation as that obtained in my copending application referred to above, but is here ac- Ycomplished using a very compact and unitary device.

There is a shock absorber included in the unit 9 which may act throughout the Vfull vrange of elevation'of the "gun 14 and which acts in the following manner: The annular chamber 141 has a gas charged therein 4to a vpredetermined pressure that may be indicatedby the -gage 146. This gas under pressure maintains the end wallsr142 and 143 of the chamber 141in `their extreme positions 4as illustrated in Fig. la, Whenever a force is appliedto the gun that tends to rotate vitabout its trunnion Aaxis 25, such force will tend to 'move the `"piston 10 within its chamber 29 located in the cylinder V16. Such tendency to move thepiston 1-0 will increase the', pressure on the hydraulic fluid located on. one side of the piston, and when such increase in pressure Vexceeds a predetermined quantity (asdetermined by the gas pressure in'chamber 141), i.e. assumes shock load magnitudes, either 'a sleeve shaped piston 150 or a similar sleevershaped piston y151 will be caused to move from its extreme position as illustrated in Figs. la and lb, to vtheleft or to the right as viewed in the drawings, and will thereby push one of the end walls 142 or 143 'a corresponding amount against the pressure of the gas contained in chamber 141. This movement of the piston or V151 will allowhydraulic iluid toilow out vof the chamber29 from the high pressure side of the piston 1l) and into thespace created by the movement ofthe piston 150er 151, and therefore the excessive pressure created by the :shock load will be absorbed. At the sarne time, hydraulic iluid will beintroduced into thecharnlber 2:9 on the low presesure side .of the piston 10, by the same `movement of the piston 150 or 151 since such movement will displace hydraulic fluid from `the chamber `67 or 83 and thisl uid will be caused to owr to the opposite side of piston I10. As soon as the'exce'ss force of the -gun 14 has been dissipated, the gas pressure in 'chamber 141 will act upon that end wall 142 or 143 which Vwas displaced, and pushrthis end wall back to its `"entferne position illustrated, while this return action will "causea reverse operation in the ilow of hydraulic viiuid 'such thatiiuid which was removed from one side inV piston '1li to chamber 29 will vbe returned and that uidwhich was-added to opposite side of piston 10 willbe Vpushed backfout ofthe chamber 29 as the piston 10 is reposi- 'tined vto its original'location. YIt maybe observed'that this shock absorbing action will allow Vthe gun to"be `dis'placec'l byfan overload or `shock while having theV gun vreturned tol its original position'as soon as the overload or'sh'ock condition has been dissipated. Such Vaction may take vplace anywhere throughout ythe full rangebf .eleva- `tion ladjustment of the gun 14. a Though this invention has been describedin one embodiment as applied to armyV tanks, it must be understood that it has many-fold applications such as in drricks, cranes, ships or trains. It can also Ybe applied'in many-types vof stationary tiltable members.

A specific embodiment of the invention has been described in-detail but this in no way limits the scope of my invention. Such details are merely illustrative offone specic embodiment. `VVarious changes and modiications will suggest Ythemselves to one skilled in the art. Therefore, `I claim as my invention: l. An'improved equilibrator-elevation cylinder unit of the hydropneumatic type for a pivoted member, comprising a compound -cylindrical unit having yhydraulic cylinderand piston means for elevating and depressing kithe'rnember, Ypneumatic chamber means within said Iunit for*applyingequilibratingfforce tothe member, sensing means for determining unbalanced forces `n"tlie*me- 11 ber, and means associated with said sensing means for regulating the gas pressure of said pneumatic chamber means.

2. An improved equilibrator-elevation cylinder unit of the hydropneumatic type for a pivoted member, comprising a compound cylindrical unit having hydraulic cylinder and piston means for elevating and depressing the member, first pneumatic chamber means Within said unit for applying equilibrating forces to the member, second pneumatic chamber means within said unit for absorbing shocks felt by the member, sensing means for detering unbalanced forces on the member, and means controlled by said sensing means for regulating the gas pressure of said first pneumatic chamber means.

3. An improved equilibrator-elevation cylinder unit of the hydropneumatic type for a pivoted member, comprisiig a compound cylindrical unit having hydraulic cylinder and piston means for elevating and depressing the member, first pneumatic chamber means within said unit lfor applying equilibrating forces to the member, second pneumatic chamber means with said unit for absorbing shocks felt by the member, sensing means for determining unbalanced forces on the member, and means controlled by said sensing means for regulating the gas pressure of said first pneumatic chamber means, -and overload relief means for allowing slippage repositioning of the member before mechanical failure in the equilibratorelevation unit takes place.

4. An improved equilibrator unit for use with vehicular mounted pivoted members, comprising a unitary cylindrical structure adapted to be pivotally fastened to the vehicle and to the member, said cylindrical structure having a hydraulic member elevating section, a pneumatic equilibration section and a pneumatic shock absorbing section, said hydraulic member elevating section comprising a hollow piston rod having 4a piston attached thereto, said piston being longitudinally movable in one end of said cylindrical structure for elevating and depressing the member, said pneumatic equilibration section comprising a cylindrical chamber in the other end of said cylindrical structure and extending into said hollow piston rod, a oating piston longitudinally movable within the hollow piston rod and separating gas in said chamber from hydraulic uid in said hollow piston rod, said shock absorbing section comprising an auxiliary gas chamber having movable walls actuated by hydraulic uid of said hydraulic member elevating section, hydraulic valve means for sensing unbalanced forces on the pivoted member, and means controlled by said hydraulic valve means for varying the quantity of hydraulic iiuid in said hollow piston rod to regulate the equilibration force exerted by the gas in said cylindrical chamber.

5. The combination of claim 4 further including overload relief means for allowing a by-passing of hydraulic fluid from one side of the piston in said member elevating section to the other side thereof whenever a predetermined excessive load is applied to the member in elevation.

6. An improved equilibrator-elevation cylinder unit of the hydropneumatic type for a pivoted member mounted on a veh1cle, comprising, a compound cylindrical unit, said unit having means for pivotally attaching its ends to the member and to the vehicle, a hollow piston within said unit, one of said attaching means being integral with said piston, a cylinder having a gas section and a hydraulic fluid section, one end of said cylinder being integral with the other of said attaching means, a oating piston longitudinally movable within said hollow piston to separate said gas section of the cylinder from said hydraulic uid section, sensing means to determine unbalanced forces on the member, and means controlled by said sensing means for varying the quantity of uid in said hydraulic fluid section to regulate the pressure in said gas section for regulating the equilibrating force of the equilibrator.

7. An apparatus for use with a member which is tilt.- able about a trunnion axis and which has a center of mass oiset from said trunnion axis, said apparatus comprising an equilibrator including piston and cylinder elements to provide varying pneumatic pressure for compensating unbalanced forces attendant upon tilting of the member, hydraulic elevating means for lsaid member including a piston rod which also serves as an element of the foregoing equilibrator.

8. The invention according to claim 7 wherein the hydraulic elevating means includes a piston structure movable with the common piston rod, and a cylinder concentric with said common piston rod.

9. The invention according to claim 7 wherein the common piston rod for the equilibrator and elevating means is hollow and wherein a floating piston is provided in said hollow rod to deiine a movable boundary between a pneumatic chamber and -a hydraulic chamber of said equilibrator, and including means for varying the amount of liquid rin the hydraulic chamber to provide varying pneumatic pressures in the pneumatic chamber of the equilibrator.

10. In an apparatus of the class described a hydropneuF matic equilibrator for a tilting gun, hydraulic elevating means including an elevating cylinder concentric with a piston rod and also including a piston secured to said piston rod, elements of said elevating means serving also as elements of the equilibrator, said last-named common elements comprising said piston rod which is hollow and including a oating piston in said rod for defining the boundary between the pneumatic and hydraulic sections of the equilibrator, and means for detecting unbalanced hydraulic forces upon opposite sides of said piston with fur-ther means controlled by the detecting means for regulating a supply of fluid to the hydraulic hollow section of the equilibrator and for variably displacing the floating piston in the hollow piston rod.

1l. A hydropneumatic elevating device -for a til/table gun including an elevating cylinder and piston and double acting means to elastically absorb excess pressures in said elevating cylinder on either side of said piston, said means including means to receive liquid from the excess pressure end of said cylinder, means to introduce a corresponding amount of liquid to the opposite end of said cylinder, and pneumatic pressure means to return the liquid from and to said cylinder when the excess pressure is dissipated.

l2. Improved hydropneumatic elevating gear for a gun having trunnions and being mounted on a base for rotation in elevation about the axis of said trunnions, comprising an elevating cylinder and piston connected between said gun and said base for controlling the gun in elevation about said trunnion axis, and shock absorbing means connected to said elevating cylinder including pneumatic cushioning means, means associated with said cushioning means for receiving liquid from the high pressure side of said elevating piston, means for simultaneously supplying a corresponding amount of liquid to the other side of the piston, said cushioning means acting to restore liquid to and from both sides of the piston when the shock has passed.

13. In an apparatus of the class described, a hydropneumatic equilibrator for a tilting gun, hydraulic elevating means Ifor said gun, said last-mentioned hydraulic means having an element which also serves as an element of the foregoing hydropneumat-ic equilibrator, said element of the hydraulic elevating means which also is the element of the equilibrator comprising a hollow piston rod, and the equilibrator including a lioating piston in said hollow rod for dening the boundary between the pneumatic and hydraulic sections of the equilibrator.

References Cited in the file of this patent UNITED STATES PATENTS Reynders et al. Aug. `l2, 1902 (Other references on following page) 13 UNITED STATES PATENTS 14 n Chinn Feb. 24, 1948 APrache: Nov. 6, 1951 Walder Jan. 6, 1953 FOREXGN PATENTS France June 4, =1912 France July 26, 1950 ttstlng O cer UNITED STATES PATENT OFFICE CERTIFICATE oE CORRECTION Patent No., @946,262 July 26T,` 1960 Lawrence Bruehl It is herebb'r certified that error appears in JChe -printed specification of the above lnumbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 39 after "axis" insert 25 mj; column 4, line T6 for lforman read from -mg column 8, llne 63, v for "Th" read The w; column 10, line 37, for "presesure: read pressure -M- column 11Y line 21., for "with" read within Signed and sealed this 4th day of April 1961\7 (SEAL) Attest ERNEST W. SWIDER ARTHUR W. CROCKER UNTTED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 2Y946262 July 26Y 1960 Lawrence Bruehl It is hereby certified that error appears in the-printed specification of the above l'numbered patent requiring correction and that the said Letters Patent should read as corrected below.v

Column 3., line 39i after axis insert w- 25 WT; Column 4, line 16Y for "form" read from mg column Bq line 63, Y for "Th" read A The w; column 10)i line 37, for "presesureread pressure u; column 11,4 line 211, for "with" read -d within "n,

Signed and sealed this 4th day o April 1961.,

(SEAL) Attest: ERNEST W. SWIDER XXX ARTHUR W. CROCKER ttestmg Ocer Acting Commissioner of Patents 

